[H-CG30] 圏外環境における閉鎖生態系と生物システム

[HCG30-02] 陸棲藍藻Nostoc sp. HK-01 の乾燥藻体の乾熱耐性に関わる機能分子

*木村 駿太^1,2、オン 碧¹、富田ー横谷 香織³ (1.筑波大学大学院生命環境科学研究科、2.日本学術振興会、3.筑波大学生命環境系)

キーワード：休眠細胞、乾熱耐性、Nostoc sp. HK-01、陸棲藍藻

Terrestrial cyanobacteria are useful for enabling bio-chemical circulation in closed bio-ecosystems, which is achieved owing to their photosynthetic and nitrogen fixing ability, utility as a food, and tolerance to harsh environments. Dried colonies of the terrestrial cyanobacterium Nostoc sp. HK-01 have a high tolerance to vacuum, UV, gamma-rays, heavy particle beams, and extreme temperatures. Tolerance to extraterrestrial environments is important for transportation to Mars. Nostoc sp. HK-01 has several different types of cells in its life cycle. The akinete (dormant cell) cell type of in Nostoc sp. HK-01 shows tolerance to dry heat. Some functional substances which provide tolerance against heat exist in the akinete cells. In this study, we investigated a property of low molecular weight compounds, which are accumulated in the akinetes of Nostoc sp. HK-01, to prevent protein aggregation after heating. The results of our study suggest that the compounds function as a compatible solute, which contributes to the dry heat tolerance of the akinetes of Nostoc sp. HK-01. The detailed mechanisms of action of the identified substances would be investigated in future studies.